Would it surprise you to know that your eyes seldom stop moving? Rapid simultaneous movement of both eyes is called saccadic eye movement, or saccade. It happens so fast, and so smoothly that we are seldom even aware of it. In fact, no other part of your body moves as quickly as your eyes, with Saccadic Eye Movement – consciously or subconsciously.
How Humans See with Saccadic Eye Movement
When you look at something, your eyes do not actually stop to rest on it. Instead, they are still constantly moving, but the movements are very quick and very slight so that you don’t even realize it. Despite the fact that your eyes never stop moving when you are looking at an object, they are taking in bits and pieces of the object to create the whole object in your mind’s eye. It is interesting to note that when we look at an object, our eyes refuse to stay fixated on it. Our focus actually moves off of the object rather quickly, and Saccadic Eye Movement actually brings the focus back to the object in question.
Saccadic Eye Movement and Microsaccades
While the eye is in constant motion, it is also constantly vibrating. Again, this vibration is so slight that we don’t feel it or notice it. The vibration occurs at a rate of 30 to 70 Hertz. This vibration serves much the same function as hitting the refresh button on a web browser. The vibration is causing your eyes to refresh the image that you are looking at, and this vibration is referred to as a microsaccade.
What Would Happen without Saccadic Eye Movement
If your eyes did not constantly move and vibrate, when you fixated your vision on an object for any length of time, you would actually be unable to see it within a few seconds. While the function of the eye is very detailed, and quite complicated, the Saccadic Eye Movement is essential for vision, but it isn’t the only type of movement in the eyes. Other types of movement are ocular drift, smooth pursuit, and ocular tremor.
Unfortunately, there are certain conditions that can cause the eye movement to slow down considerably, and possibly even stop it altogether, which of course causes extreme vision problems. These problems are usually caused by an imbalance in the vestibular system, but they could also be caused by a damaged brainstem.